The population of hearing-impaired and severely hearing-impaired youth and adults is approaching 50 million in the United States and is growing rapidly. The plight of the severely hearing-impaired can be very difficult. The ability to enjoy live theater, a religious service, or even a movie is more important than just for entertainment purposes. For children, it enables critical development and contact with the everyday world. For adults or the elderly it allows enjoyment, mental stimulation, and social contact that is important. However, due to hearing impairment, some youth and adults may no longer be able to obtain these benefits from these activities.
Hearing-assist systems, as found in venues such as churches, movie theaters, live Broadway theaters, and similar venues attempt to provide amplified sound to the hearing-impaired. Many are legally required to do so. The legal requirements do not go into any significant detail with regard to actually optimizing the sound for a hearing-impaired person. A typical venue operator (and even the sound production staff) is understandably focused on other high priority tasks, and the hearing-assist system is often described as ‘the end of the food chain’, in that minimal effort is made improving the hearing-assist system. Most often, the sound from the hearing-assist system is perceived by the user to be unintelligible and in frustration the user may give up and further retreats from the venue, and even society.
In an attempt to maintain social contact many hearing-impaired individuals have tried hearing-assist systems in venues such as movie theaters, live Broadway theaters, and churches without success. They have been unable to hear or understand the dialog on typical headset, T-loop, and similar hearing-assist systems and have essentially retreated from these important elements of every day society. The issue or challenge is that typical hearing-assist systems were not optimized or designed for use in these venues.
More specifically, the poor hearing-assist sound quality as perceived by the hearing-impaired person in such venues results from the fact that most hearing-assist systems appear to be designed for the home, museum, or classroom environment, perhaps because cumulatively these markets may be larger than the venues of interest herein. The hearing-assist sound is typically transmitted to a headset or hearing aid (such as a cochlear implants) by FM, infrared, magnetic, or a similar coupling. It is important to recognize that the hearing-impaired person may still hear all or portions of the venue's ambient (audience) sound directly either through one ear being good, through their natural hearing's frequency response eliminating but some sound frequencies, via a hearing aid system simultaneously picking up ambient sound such as echoes and reverberation, through low-cost headsets not reducing ambient room sound, or even through body and bone conduction of low frequency sound.
Since there is a time delay between the sound waves propagated through the air and the representations of the sound propagated electronically to a device, as well as the energies in the ambient propagated sound, there may be significant interference between the ambient sound and the hearing assisted electronic sound. This interference can be extremely confusing and is likely to render the ultimate signal actually heard by the hearing-assisted user as gibberish.
The problem for the hearing-assist user in such venues will be referred to as a psychoacoustic effect. That is, as used herein, psychoacoustics is concerned with how sound is perceived, and a psychoacoustic effect is the psychological and physiological response by a hearing-impaired hearing-assist user to receiving sound in a venue. This sound heard by the hearing-assist user can include a mix of ambient sound as well as electronically transmitted sound.
As will be discussed in greater detail below, the psychoacoustic effect for a hearing-assist user occurs in any venue where some sound heard by that user is ambient and some sound to be heard by the user is electronically transmitted. In small venues, such as in a home or a classroom or the like, this effect is not significantly affected by differences between ambient sound and electronic sound and tends to not result in the masking or garbling of effects present in the original sound; however, in large venues such as theaters, concert halls, opera houses, or the like, the effect can be sufficiently significant to noticeably degrade the person's enjoyment of the program in the venue. The prior art has not adequately addressed this issue. Further developments are therefore required.